I've been told to not bother maintaining a debian/ because the first step in Debian is to rm -rf it
What you’ve been told is right. While it could be surprising at first, it’s because the Debian policy is that the packaging should be done by the distribution maintainers, not the upstream developers.

So you as an upstream developer should not have to spend time on that, all that is expected from upstream is stable releases and a sane dependencies policies. It’s the job of the distribution to then turn that into a neat package.

Of course it can happen that the upstream developer is at the same time the distribution maintainer (it’s my case for the software I develop and its packaging into Debian). But it’s still two distinct roles that should ideally not be mixed together. Different skills and mindsets are required for both tasks.

CC: @hailey@hails.org